PRE-DRAWING AND AIR-BULGING TECHNOLOGY OFSUPERPLASTIC FORMING FOR AUTOMOBILE MODELS

摘要

The forming of automobile models with big and complexrnsurfaces is difficult in the practical work. The phenomena ofrncracking, time-consuming and non-uniform distribution ofrnsheet thickness occurs in the forming process by using therntraditional superplastic air-bulging technology. Based on therntruth of metallic materials having higher tensile-strength atrnthe superplastic lower-temperature, this paper presents arntechnology combined with pre-drawing at the superplasticrnlower-temperature and air-bulging at the optimal superplasticrntemperature. Finite element method is employed to simulaternthe forming process of an automobile-model by using bothrnthe combined technology and the traditional superplastic airbulgingrntechnology. Finally, this paper compares the resultsrnof simulations and experiments, and draws the conclusion that,rnthe combined technology is superior to the traditionalrnsuperplastic air-bulging technology for the automobilemodel'srnshaping.